DE1188752B - Lubricant based on mineral oils containing complex compounds of molybdenum blue with phosphorus compounds - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

ClOm

German class: 23 c-1/01

Number: 1188 752

File number: 114658IV c / 23 c

Filing date: April 3, 1958

Opening day: March 11, 1965

Lubricants often have to have higher temperatures, reaching 120 ° C, for a very long time or exceed, endure. For this reason, lubricating oils for internal combustion engines must be tested be subjected to change, where 5 e.g. the lubricant in open air at 115 ° C heated for 72 hours in the presence of metals such as copper, iron, aluminum or lead will. The result of the test is favorable if neither deposits nor metals form are attacked and after dilution with normal hexane no precipitation of asphalt materials is recognizable.

The molybdenum complexes which are soluble in hydrocarbons are known to be of particular importance as additives in lubricants. Because they are particularly under the action of temperatures that by Friction are reached, disintegrate, they form a protective coating on the metallic pieces, which prevents the tearing away of metallic particles and thus provides excellent lubrication, in particular guaranteed under extreme printing conditions.

Among the known molybdenum complexes, the complexes to be mentioned are primarily those which Molybdenum blue forms with phosphorus compounds, such as trialkyl phosphates, dimethylamidodialkyl phosphates, Trialkyl thiophosphates, dimethyl amido dialkyl thiophosphates and alkyl phosphonates such as them correspond to the formulas listed below:

OR

NR ' ₂

OR

O =

OR

NR ' ₂

S =

OR

and O =

S =

OR '

OR

OR

OR

in which R and R 'represent aliphatic radicals having 2 to 12 carbon atoms.

In these compounds, all acidic functional sites in the molecules of phosphoric acid or thiophosphoric acid are blocked by the alkyl or alkyl amide residues. However, they partially decompose if they ^{are exposed to relatively high temperatures of about 120 °} C. over a long period of time, which the lubricating oils for engines in particular have to withstand. They can therefore only be used where the lubricating oil has higher temperature lubricants based on mineral oils
with a content of complex compounds of molybdenum blue with phosphorus compounds

Applicant:

Institut Frangais du Petrole, Paris

Representative:

DipL-Chem. Dr. phil. E. Sturm, patent attorney,
Munich 23, Leopoldstr. 20th

Named as inventor:

Georges Hill, Ville d'Avray, Seine-et-Oise;

Moise Lerer, Paris (France)

Claimed priority:
France of April 19, 1957 (736 800),
dated!. August 1957 (744697)

temperature is not exposed before it with the metallic pieces which are lubricated should have been brought into contact.

These difficulties arise when a lubricant based on mineral oils is used avoided a content of complex compounds of molybdenum blue with phosphorus compounds the general formula

OR '

S = P ^

OH

has, where R is hydrogen, an alkyl radical having at least 4 carbon atoms, optionally one alkyl-substituted aryl radical or a polyoxyethylene monoether radical, and R 'is equal to R, but not hydrogen.

These complexes of molybdenum blue decompose at temperatures that are reached by friction during lubrication (in particular at 200 to 220 ^° C.) and are stable at temperatures of up to 115 to 120 ^° C., at which the lubricating oil is used in internal combustion engines.

The great stability of the complex compounds obtained in this way appears to be due to the bond of the molybdenum

509 518/422

blue to be based on the free acidic functional site, resulting in a stable reaction product.

The alkyl chains, like the aryl radicals, can be replaced by halogens or sulfur-containing Groups may be substituted.

The phosphorus compounds of molybdenum blue are made by using one of the one or ' dibasic phosphorus compounds as mentioned above with a partially reduced solution reacts with molybdic acid, which is produced under the conditions described below is.

Sodium molybdate is made up to 1 part of sodium molybdate in an aqueous solution of sulfuric acid about 15 parts of sulfuric acid and 40 parts of water (parts by weight) dissolved. This solution then becomes partially reduced with about 0.015 parts of aluminum. This gives a solution with one oxidation level: M02O53M0O3.

The same solution can be obtained by using 3 parts of the unreduced ones previously described Mix the solution with 2 parts of the same solution, resulting in pentavalent molybdenum by 0.015 parts Aluminum is reduced to 1 part sodium molybdate.

The composition of the unreduced solution of sodium molybdate is given as an example only cited.

Any other composition can be used without disadvantage provided that the Solution after partial reduction a complex of molybdenum blue only in the presence of the organic phosphoric acid ester.

Instead of sodium molybdate, other molybdates can be used, such as potassium or Ammonium molybdate, or even anhydrous or dehydrated molybdic acid, obtained by acid treatment is made soluble. One can also replace the sulfuric acid with other mineral acids, which are at neither oxidize nor reduce the working conditions, replace.

The acid phosphoric acid thioester, which is allowed to react with the solution of molybdic acid, are produced according to known processes.

The molybdenum complexes are formed by the reaction of one of the acidic phosphoric acid esters mentioned above obtained with the reduced solution of molybdic acid under the following conditions:

In a flask with three side necks containing a stirrer, a reflux condenser and a thermometer carries, or in any equivalent apparatus, one carries out the Morybdenum solution, which partially reduces is, one and then the acidic phosphoric acid ester in respective proportions of 1 to 3 moles of ester per mole Molybdic acid. These proportions are in no way limiting, for it is evident that the The smaller the ester to molybdic acid ratio, the richer the product will be in the molybdenum complex will.

To make it easier for the molybdic acid to come into contact with the ester, it is sometimes useful to use the Esters with a neutral (non-reactive) solvent such as hexane, heptane, benzene or Xylene, to be diluted. You can z. B. Use an amount of solvent that is the same in weight that of the ester is.

The temperature of the reaction is preferably kept between 50 ^° C. and the boiling point of the molybdenum solution (at about 105 to 110 ^° C.). A temperature below 50 ⁰ C would lead to the Ubelstand that one could not maintain a sufficient reaction rate.
The duration of the reaction changes with temperature. At 50 ⁰ C the reaction lasts several hours. At the boiling point of the molybdenum solution, it is reduced to just 15 minutes. The progress of the reaction can easily be followed with a colorimeter. You get good results when

the reaction is ended as soon as the reaction product dissolved in hexane has an extinction maximum at a wavelength of about 610 πΐμ receives.

The molybdenum complex thus obtained contains variable amounts of phosphoric acid ester.

One can obtain products that are very rich in molybdenum complexes, either by fractionation with a solvent or, even better, by dissolving it in a solvent The reaction product leads over columns which are filled with absorbents such as silica gel are. Instead of letting the acidic phosphoric acid ester act on the solution of molybdic acid, which has previously been partially reduced, one can likewise prepare the complexes of molybdenum blue, by immediately treating the phosphorus compound and the aluminum with an aqueous acidic and unreduced solution of molybdate, which is not very concentrated (about 150 mg Molybdate per cubic centimeter of water) and sufficiently acidified (at least 0.5 g sulfuric acid of 66 ° Be per cubic centimeter of water).

The reaction mixture is kept boiling for about 15 minutes. After vigorous cooling the solution is given a neutral, non-reactive solvent in the reaction mixture, such as hexane, heptane, benzene or xylene, in an amount by weight which, for. B. that of the phosphoric acid compound is equivalent. The molybdenum blue then forms exclusively in the one floating above organic phase. Separated from the solvent by vacuum distillation, it turns into the Form of a strongly blue colored oily liquid, the variable amounts of phosphoric acid ester some of which are retained by any of the appropriate means described above can. The portion of molybdate that has not reacted is recovered in the aqueous phase and used again.

The molybdenum blue of the thiophosphorus compounds has the necessary properties, namely:

1. A high stability at temperatures up to 120 ⁰ C. It can be subjected to tests on changes in the open air, as has been mentioned above for (72 hours at 115 ° C in the presence of metals) without a change or decomposition subject;

2. the ability to decompose at temperatures of about 200 ⁰ C. A great solubility in mineral oils.

Another series of particularly interesting thiophosphates of the formula:

0 (CH ₂ CH ₂ O) _n C ₆ H ₅
S = PiO (CH ₂ CH ₂ O) _n C ₆ H ₅

OH
(where η has a factor of preferably between 4 and 9

means) are characterized by their high solubility in polyethylene glycols; the complexes, which they form with the molybdenum blue are equally soluble in the polyethylene glycols and can advantageously be used in combination with these as lubricant-forming elements. These Compounds can be obtained if one starts from phenol monoethers of polyethylene glycols, which result, for example, from the condensation of phenol with ethylene oxide.

example 1

Production of a molybdenum compound of
acid dicetyl thiophosphate

A solution containing 100 parts by weight of sodium molybdate (Na ₂ MoO ₄ · 2 H ₂ O), 4200 parts by weight of water and 1450 parts by weight of sulfuric acid at 66 ° Be is reduced with 148 parts of aluminum when it is boiled. The mixture is allowed to cool to 90 ⁰ C and then added 70 parts by weight acidic Dicetylthiophosphat to. This temperature is maintained for 30 minutes while stirring the mixture. The stirring is then stopped and the mixture is allowed to cool to room temperature. The aqueous layer is then removed by siphoning and a blue complex is extracted with 56 parts by weight of benzene. After removing the weak aqueous layer that still forms, the mixture is dried by filtering through a column containing anhydrous magnesium sulfate. It is then concentrated on the water bath, first under normal pressure, then under reduced pressure of 15 mm Hg. 74 parts by weight of a solid, crude product of blue-black color which can be used as an additive for mineral oils are obtained in this way. This crude product can be improved by enrichment in the molybdenum complex if you proceed as follows: Dissolve 45 g of the crude product in 100 ecm of petroleum hexane and pass the resulting solution through a column with an internal diameter of 30 mm and a height of up to 2 m is filled with activated powdery silica gel (grain size 25 to 40). The column is then washed with the hexane until the solvent runs off almost colorless. The hexane solution is concentrated on a water bath, first under atmospheric pressure, then under reduced pressure of 15 mm Hg.

The end product is then obtained as a glossy lacquer with a blue-black color. It's in organic Liquids and especially in hydrocarbons such as hexane, heptane, benzene, toluene, mineral oils and the like, which it stains strongly blue, soluble.

When the crude product was colored in a hexane solution, the following results were obtained :

Apparent extinction coefficient (Coefficient d'extinction apparent) (Λ = 610πΐμ) Ei "rf *" ¹ = 0.70.

The product enriched in complexes gave:

Apparent extinction coefficient (Coefficient d'extinction apparent) (λ = 610πΐμ) EiSf ™ = 2.19.

How these solutions adequately follow Lambert - Beer 's law can be seen that after passing through the silica gel, the product became three times richer in molybdenum complexes is.

This enriched product, in solution in a pure mineral oil, gave SAE 30 for the respective Concentrations of 1 and 4% with a "four-ball machine" (that of B ο e r 1 a g e in the Journal "Engineering" of July 14, 1953) the following comparison results:

Experiments with the "four-ball machine," which use the molybdenum blue complex
concern with acid dicetyl thiophosphate

15th Applied
charges 25th 180 ■ 30 200 oil SAE 30 2 oil SAE 30 + oil SAE 30 + > 60 190 pure 2.5 1% molybdenum 4% molyb > 60 ^k s Time in moment complex Danish complex > 60 120 liches the seizure occurs 150 Seizure Seconds 170 > 60 > 60 > 60 > 60 > 60 8th > 60 moment liches Seizure

The table above clearly shows that the time after which seizure occurs is clearly improved if a relatively small amount of the molybdenum complex of acid dicetyl thiophosphate is added to the base oil.
It should also be noted that the balls at

each time the experiments were carried out. The use of in previous attempts used balls would have allowed it with progressively growing batches, thanks to the persistent deposition of a layer of the molybdenum compound on the balls without higher pressures To achieve seizure.

On the other hand, the molybdenum blue of dicetyl thiophosphate, regardless of whether it is on the Molybdenum complex is enriched or not, no change or decay after getting it an oxidation test for 72 hours in the open air in the presence of copper, iron, aluminum or exposed to lead.

Example 2

Manufacture of a molybdenum compound of
acidic dilauryl thiophosphate

The same partially reduced molybdenum solution as described in Example 1 is boiled treated for 15 minutes with stirring with 70 parts by weight of acidic dilauryl thiophosphate. After separation, extraction with hexane and compression, a semi-liquid with a strong blue color is obtained Product whose stability was carried out under the same conditions as described in Example 1 Oxidation test has been proven.

Example 3

45 The following results were achieved:

Manufacture of a molybdenum compound
of acid dioleyl thiophosphate

The procedure is as in Example 1, adding the acidic dicetyl thiophosphate by the same parts by weight replaced by acid dioleyl thiophosphate. This gives 70 parts by weight of the strongly blue-colored Molybdenum complex in liquid form, which is also characterized by a very high stability, after being subjected to the oxidation test described above.

Example 4

Manufacture of a molybdenum compound

of distearyl thiophosphate

The procedure is as in Example 1, replacing the acidic dicetyl thiophosphate in equal parts by weight with distearyl thiophosphate and using the difference is that 56 parts by weight of benzene are added to the reaction mixture and under reflux of benzene heated.

After compaction, 70 parts by weight of a crude complex of blue color, which at Performing the above-described oxidation test no change or any disintegration shows.

No protection is sought for the production of the complex compounds.

In terms of technical application, the compounds claimed offer considerable advantages over this the compounds known from the prior art, including those according to French patent specification 1099 953. The following technical data refer to a Comparison between:

(I) the molybdenum blue complex compound from the phosphorus compound having the formula

S = P (OCi ₆ H ₃₃ MOH)
according to the present connection and

(II) the molybdenum blue complex compound from the phosphorus compound having the formula

S = P (OC ₁₆ H ₃₃ ) S
according to French patent 1 099 953.

These two compounds were tested in a test with the Faville machine. To this end the two compounds were dissolved in proportions of 2% in pure mineral oil SAE 30.

Wedging load (kg) 80 tension 120 140 300 100 1075 1525 300 515 1050 1230 2% of (I) in SAE 30 oil 280 510 620 510 2% of (II) in SAE 30 oil 490 oil SAE 30

Furthermore, in contrast to the information in the French patent specification, have those described therein Molybdenum blue compounds only have a mediocre stability, which is far less than that of the compounds of the present invention.

So is z. B. the 2% solution of the compound (II) in oil SAE 30 with prolonged heating to 120 ⁰ C is not stable. In the experiments carried out at a temperature of 120 ^° C. for 9 hours, the mixture always deposits an insoluble precipitate which contains molybdenum. Along with this precipitation there is a progressive decrease in the performance of the oil remaining on the Faville machine.

In contrast, the 2% strength solution of the compound (I) in the oil SAE 30 ^{remains unchanged after maintaining a temperature of 120 °} C. for 72 hours. At the end of this experiment, the performance of the connection did not change significantly.

Claims (1)

Claim: Lubricant based on mineral oils, characterized by a content of complex compounds of molybdenum blue with phosphorus compounds of the general formula OR ' S = OH where R is hydrogen, an alkyl radical having at least 4 carbon atoms, one optionally alkyl-substituted aryl radical or a polyoxyethylene monoether radical and R 'is equal to R, but not hydrogen. Considered publications:
French Patent No. 1 099 953. Legacy Patents Considered:
German Patent No. 1 123 069.